The present invention relates generally to a keymat or keyboard to be used on a portable electronic device and, more particularly, to a keymat or keyboard that has a plurality of illuminated keypads.
In a portable electronic device, such as a mobile phone, a communicator, a personal data assistant (PDA), a portable communications device or the like, a keyboard is usually used to provide a User Interface (UT) between the user and the device. Typically, the keyboard includes a plurality of alphanumerical keypads and/or function keys to allow a user to select a function or to key a value into the device. When the ambient lighting is inadequate, it is essential that the keypads or keys are illuminated so that the user can correctly select the keys.
In a conventional illuminated keyboard including a keymat and an underlying circuit board, discrete light-emitting devices (LEDs) are surface-mounted on the circuit board to provide illumination to the keypads thereabove. Alternatively, light guides or conduits are used to guide light from one or more light sources on the circuit board to the proximity of the keypads. Conventionally, all the LEDs mounted on the circuit board, as described above, are turned on or off at the same time. Thus, like the light guides, the LEDs for illuminating the keypads cannot be selectively controlled. Furthermore, the surface-mounted LEDs are bulky and their power consumption is usually high. Because of their bulkiness and high power consumption, these surface-mounted LEDs are not optimal for use in a small portable electronic device.
On a mobile phone, a communicator and any other portable communications device, there is usually an information display panel, such as an LCD panel, for providing information to the user. Typically, one or more softkeys are used to guide the user to operate the device. A softkey has a function displayed at a designated area of the display panel and an associated keypad located outside the display panel adjacent to the designated area. A user can use the associated keypad to choose the function of the softkey. For example, two softkeys are often used in a Nokia mobile phone to assist a user to operate the mobile phone. When the mobile phone is turned on, the initial functions of these two softkeys are shown as xe2x80x9cMenuxe2x80x9d and xe2x80x9cNamexe2x80x9d at their corresponding designated areas. By choosing the xe2x80x9cMenuxe2x80x9d function through the associated keypad, the displayed functions of the two softkeys will change to xe2x80x9cSelectxe2x80x9d and xe2x80x9cExitxe2x80x9d . The xe2x80x9cSelectxe2x80x9d and xe2x80x9cExitxe2x80x9d functions are xe2x80x9crequestsxe2x80x9d to the user, asking the user to choose the next course of action regarding the use of the mobile phone. In this way, the user is provided with a guide to operate the device according to the displayed functions of the softkeys at a given moment. However, this type of softkey has several disadvantages, as described below. Because the function of the softkey is shown at a designated area within the display panel, the use of softkeys significantly reduces the available area for displaying other messages on the display panel. Thus, for practical reasons, the number of softkeys is limited to only a few. Moreover, it has been found that some users are confused over the xe2x80x9crequestsxe2x80x9d shown at the designated areas of the display panel and usually cannot relate the requests to the associated keypads. This psychological obstacle is a real problem for traditional softkeys.
It is advantageous and desirable to provide a keymat, wherein the illuminating light sources are small and have low power consumption, and wherein illumination of the keypads can be selectively controlled. Furthermore, the illuminated keypad areas can include alphabetical letters, numerals, text and/or graphical images to indicate the functions of the keypads so that these keypads can be used to replace the softkeys in certain portable electronic devices.
It is an objective of the present invention to provide an integrated keymat to be used on a portable electronic device, wherein the keymat includes one or more emissive keypads having legends or other key indicating marks provided thereon, and wherein the keypads can be individually illuminated so as to allow the legends on the keypads to become more visible. Accordingly, the keymat comprises separate light-emitting components provided on the emissive keypads and electrodes for activating the light-emitting components in order to illuminate the keypads, wherein the electrodes are operatively connected to electrical connectors which provide electrical power to the electrodes, and wherein the electrical connections to the electrodes are controllable so that the keypads can be selectively illuminated.
Preferably, the light-emitting component in a keypad comprises a single light-emitting pixel to illuminate the legend on the keypad.
Alternatively, the light-emitting component in a keypad comprises two or more light-emitting pixels which can be selectively activated to illuminate one or more segments of the legend on the keypad.
Alternatively, the light-emitting component in a keypad comprises a plurality of light-emitting pixels forming a pixel matrix, wherein the pixels of the matrix are individually addressable so as to allow one or more pixels within the keypad to be selectively activated to form a selectable illuminating pattern.
Alternatively, the light-emitting component in a keypad comprises a plurality of light-emitting segments, wherein the segments are individually addressable so as to allow one or more segments within the keypad to be selectively activated to form an illuminating pattern in a form of an alphanumerical or other symbol.
The integrated keymat of the present invention can be integrated into a circuit board having a control circuit which controls the activation of the light-emitting components, wherein the circuit board can be rigid, flexible or of any other form.
The integrated keymat of the present invention can be integrated into a circuit board having a display panel which can be used to display information related to the activated light-emitting components, wherein the circuit board can be rigid, flexible or of any other form.
Preferably, the integrated keymat of the present invention further includes all the required circuitry to control all the components on the integrated keymat in order to minimize the number of electrical contacts to the keymat down to a few power supply contacts and data line contacts.
It is possible that the integrated keymat also includes one or more transparent, magnifying pads to magnify the legends on the keypads or the legends on a display area.
It is also possible that the emissive keypads be separately integrated into a circuit board having a control circuit which controls the activation of the light-emitting components, wherein the circuit board can be rigid, flexible or of any other form.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 1 to 11b.